Jakarta – Floods have been reported in several areas in Jakarta including in Cililitan-Halim, Kebon Pala and Klender. More places are also expected to experience flooding due to heavy rains since yesterday. Some media has also reported that the Fish Market Water Gate is at Siaga II, and reminded people living in Kamal Muara, Kapuk Muara, Penjaringan, Pluit, Ancol, Kamal, Marunda, Cilincing and Kali Baru to be aware of potential flooding.
Until now, the most updated reports on which points were affected by the flood were through the Pantau Banjir Jakarta (Jakarta Flood Monitoring) website. According to the Pantau Banjir Jakarta Team, geographically, DKI Jakarta is a lowland between the upstream and the coast. Here are the 3 main reasons Jakarta experiences frequent flooding:
- Local Rain Flood. The rain that occurs with high intensity for a long duration in the Jakarta area will fill waterways and sunken areas. If it is no longer stored, the water will overflow, causing flooding. In addition, the drainage dimensions of the city of Jakarta are designed to accommodate water discharge with a maximum rainfall of 120 mm/day. However, in some extremely heavy rains that have occurred in Jakarta, the rainfall exceeds this capacity. For example, on January 1, 2020, Jakarta’s rainfall reached 377 mm / day and was the highest for 24 years. So that the floods hit most of the capital city.
- Delivery Flood. Because it is in a low-lying area and has 13 rivers, Jakarta can be flooded if rain occurs upstream of the river. Rain with high intensity in the upstream area (West Java and Banten) will be carried through the river to Jakarta before releasing into the sea. This is what makes the river that empties into Jakarta overflows and causes flooding. At certain conditions the river flow capacity in Jakarta is not sufficient to accommodate water, resulting in a runoff on several riverbanks in Jakarta.
- Flood Rob. Apart from rain and water discharge from upstream, Jakarta is also vulnerable to tides (Rob). This usually occurs in the coastal or seaside areas of Jakarta. Now, apart from the tide of seawater, land subsidence in North Jakarta also affects the increase in tidal flooding.
There are still many areas that are inundated by floods that have not/are not reported systematically, making it difficult to analyze. This article discusses where flood data can be used as a reference other than on social media. Some of the official sources of information from the Indonesian government regarding flood disasters, namely:
- Pantau Banjir Jakarta (pantaubanjir.jakarta.go.id)
This website is the most complete, with Data and 4 Interactive Maps which are considered “good” and updated (some have the last updated information “a few seconds ago”). It has:
- 3 Dashboards (not updated):
- Flood Scenario Analysis (not updated, last data June 10, 2020)
- Flood Public Dashboard (not updated, last pump data on 13 December 2020)
- A dashboard of the Department of Water Resources (last updated 29 January 2020)
- 4 Interactive Maps:
- Flood Information Map (quite updated, last updated 20 February 2021)
- Flood Map Based on RT (last flood data update on 20 February 2021, 22:13)
- Flood Scenario Map (written in the right corner, last update a few seconds ago)
- Flood History Map. This map has a 2010 – 2020 Jakarta Flood History Map which features a shiftable year placement (and could be up to 2021, but it is not known until what date it is in 2021, 2020 Flood Prone Locations, Evacuation Locations, and 2015-2020 Flood Analysis Against Land Use.
This flood data source was obtained from the Provincial Disaster Management Agency DKI Jakarta with the data source of the floodgate from the Water Resources Department of Prov. DKI Jakarta (poskobanjirdsda.jakarta.go.id), and the source of regional maps from the Department of Human Settlements, Spatial Planning, and Land Prov. DKI Jakarta (jakartasatu.jakarta.go.id).
In the home section, there is also information on Water Level and Available Pump Data. In the Water Level Data information table, there is information on the category whether it is included as a floodgate or observation post, the last updated date and time, the flow and water level, and the alert status. Then in the Available Pump Data, there is the area where the pump is located, the date and time it was last updated, the total pump, and the status of the pump being operated or alerted.
Note: The Jaki application (Jakarta now) directs users to open this Pantau Banjir Jakarta website (not integrated).
- BPBD DKI Jakarta Province (bpbd.jakarta.go.id)
The website of the Jakarta BPBD (Regional Disaster Management Agency) is not updated with the latest update on February 2, 2021 for DKI Jakarta Disaster Incidence Data. The interactive map that is owned also only has 20 flood points originating from the Disaster Map (petabencana.id).
- Jakarta Open Data (data.jakarta.go.id)
In the Data Collection section for DKI Jakarta Flood Prone Area Data, the last update was in 2019. Created on 18 May 2015 with the source of the Regional Disaster Management Agency (BPBD) with a frequency of publication once a year.
From these sources, the Pantau Banjir Jakarta source is the most updated. With a lot of details, the DKI Jakarta government should be able to do several things (which according to the author cannot be found on the website but are useful for preventing and mitigating flooding):
- Pump Operational Analysis of Water Flow and Height
There is information about the availability of pumps and how high the water is in Jakarta, which should be used to find out which water flow is most critical for it, mitigate flooding with a pump automation system, and find out which areas require additional pumps to accelerate the decrease in water levels.
- Flood Prone Area Categorization for Placement of Evacuation and Logistics
This may invite negative sentiment from businesses in the property sector because this categorization will reduce the selling price of land or property (even though potential buyers can already see it on the interactive map on the Jakarta Flood Monitoring page). This categorization is needed in order to map how many potential households are affected, how many people could potentially be evacuated, and how much logistics need to be prepared.
- Combining Weather Analysis and Points 1 and 2 Above to provide Early Warning Notification
Weather is often used as “the culprit” of the floods that occur every year, but according to the author, in-depth analysis of the weather should be carried out both from the academic and practitioner side to create a benchmark for disaster “prediction factor”. With this Early Warning Notification, it is hoped that the public will be more aware of the type of weather that can cause disasters such as floods.